Incentive spirometers are used in respiratory therapy to measure the breathing capacity or the sustained maximal inspiration of a patient. Typically, an incentive spirometer will include a light ball which can float in the air stream created by the breathing patient, to indicate the flow velocity, which, in turn, is a function of the vigor and depth of the patient's breathing.
Nebulizers are used in respiratory therapy to provide a liquid mist to a stream of gas, typically oxygen-air mixtures, which is conveyed to a patient. The mist that is added to the air stream may include water for the humidification of the oxygen supply to the patient, but also bronchodialators or mucolytic agents may be added and conveyed directly to the inner recesses of the lungs in mist form by the breathing of the patient.
Generally, nebulizing devices operate continuously, using an aspiration type device to suck up the liquid for nebulizing into a stream of oxygen gas, being forced through a nozzle by means of the well-known Bernoulli's principle. Accordingly, when the patient is not breathing, or is exhaling, the mist-laden oxygen tends to diffuse out of the device carrying the medicament with it.
In accordance with this invention, a nebulizing device is disclosed in which nebulization takes place only when a suction pressure is applied to the nebulizing chamber, for example, when a patient is breathing in. Furthermore, the device of this invention can be used as an incentive spirometer since the device may be adjusted so that the patient must breathe in with a certain minimum amount of vigor for nebulization to take place. Accordingly, the patient and a respiratory therapy technician can determine whether or not the patient is successfully meeting a specified breathing exercise goal by the use of the device of this invention, while simultaneously the same device can be used to provide nebulized gases to the patient.
Accordingly, since the device of this invention operates to nebulize liquids in the gas stream only on voluntary inspiration, the disadvantages of forced machine-controlled inspiration which are frequently, currently used are avoided. If natural, deep breathing becomes painful, the patient will stop inhaling, where a machine would continue to pressurize and possibly damage the lungs.